The present disclosure relates to video input devices which receive a plurality of digital video signals, and select and output one of the received digital video signals.
In recent years, the use of video playback apparatuses which have an interface conforming to the high-definition multimedia interface (HDMI) standard, with which uncompressed digital video signals can be transmitted, have grown rapidly. Along with this, the HDMI interface has also been widely used in video receiver apparatuses, such as a television (TV) set etc., which receive digital video signals, and an increasing number of video receiver apparatuses which have two or more HDMI interfaces have become available. In HDMI, high-bandwidth digital content protection (HDCP) for preventing unauthorized copying is employed to allow digital video signals to be transferred only between authenticated apparatuses.
In the video receiver apparatus which has two or more HDMI interfaces, HDMI ports are changed by operating a remote control etc., and video received via a selected HDMI port is displayed on a monitor. In conventional video receiver apparatuses, a video playback apparatus connected to a selected HDMI port is activated by activating the hot plug detect of the HDMI port to receive video, while the hot plug detect of an unselected HDMI port is kept inactive. In other words, when HDMI ports are changed by using a remote control etc., the hot plug detect of a selected port transitions from the inactive state to the active state, and a video playback apparatus connected to the selected port is initialized. Moreover, in the video playback apparatus, an HDCP authentication process is performed before a video signal is output. When HDMI ports are changed, a video playback apparatus connected to a selected HDMI port needs to start over from initialization, and therefore, it takes a long time to output an image when the ports are changed (this time is also hereinafter referred to as a “display waiting time”). Therefore, in order to reduce the display waiting time that it takes to output an image when HDMI ports are changed, it is necessary to remove the initialization of a video playback apparatus. To do this, however, the hot plug detect of an unselected HDMI port needs to be in the active state. However, the conventional video receiver apparatus has only one circuit that performs the HDCP authentication process, and therefore, is allowed to perform the HDCP authentication process only for a selected HDMI port, i.e., is not allowed to perform the HDCP authentication process for an unselected HDMI port. Therefore, even when the hot plug detect of an unselected HDMI port is activated, the HDCP authentication process cannot be performed on the unselected HDMI port. As a result, when HDMI ports are changed, a video playback apparatus connected to a selected HDMI port needs to start over from the HDCP authentication process, and therefore, the display waiting time cannot be reduced.
As a technique of reducing the time that it takes to output an image when HDMI ports for receiving video data are changed, Japanese Patent Publication No. 2008-306232 proposes a video receiver apparatus, for example.
FIG. 37 shows an example configuration of the video receiver apparatus of Japanese Patent Publication No. 2008-306232. The video receiver apparatus of FIG. 37 includes authentication ICs 009 and 010 which are provided for a predetermined number (here, two) of HDMI ports 003 and 004 (one authentication IC for each HDMI port), and perform an authentication process on external apparatuses 001 and 002 connected to the HDMI ports 003 and 004, respectively. An MPU 005 of a digital broadcast receiver includes a terminal selector 014 which selects one HDMI port 003 (004) as a video input terminal based on an operation input received via a remote control 006, a video receiver section 015 which receives video information from the external apparatus 001 (002) connected to the selected HDMI port via the corresponding authentication IC 009 (010), and a display controller 016 which outputs the received video information to a display 008.
A video signal encrypted by HDCP is transferred between the external apparatuses 001 and 002 and the video receiver apparatus of FIG. 37, and the received video signal is input via the authentication ICs 009 and 010. The authentication ICs 009 and 010 are used to perform HDCP authentication on the HDMI ports 003 and 004, respectively. A connection determiner 012 determines whether or not an external apparatus is connected to the HDMI port 003 or 004. When the connection determiner 012 determines that an external apparatus is connected to the HDMI port 003 or 004, the authentication IC 009 or 010 corresponding to the HDMI port 003 or 004 for which the presence of an external apparatus is determined performs an authentication process on the external apparatus. Thus, the authentication process is performed for the HDMI ports separately, whereby the time that it takes to display an image on the monitor can be reduced.